In wireless communication systems, traffic channel configuration is used for designating various parameters adopted by downlink/uplink traffic channels, such as coding scheme, coding rate and modulating scheme. Based on specific traffic channel configuration, a downlink/uplink physical layer processes baseband data and transmits the processed data through the traffic channels.
In conventional wireless communication systems, traffic channel configuration reassignment is acknowledged and confirmed in a handshake manner. When a base station (BS) needs to reassign the downlink/uplink traffic channel configuration, the BS firstly specifies traffic channel configuration with a set of parameters, and loads the traffic channel configuration into a reassignment message which is then transmitted to a terminal. If the terminal parses the reassignment message correctly, the terminal uploads an acknowledgment message to the BS, and records reassigned traffic channel configuration information for receiving or transmitting traffic data.
FIG. 1 is a flowchart illustrating a conventional method for reassigning traffic channel configuration. As shown in FIG. 1, according to a conventional reassignment method, either of the following two situations may occur after a terminal sends an acknowledgment message:
Situation 1, as shown in FIG. 1(a), if the acknowledgment message received by a BS is correct, the BS will use the reassigned traffic channel configuration to receive and transmit traffic data;
Situation 2, as shown in FIG. 1(b), if the acknowledgment message received by the BS is incorrect or the BS does not receive the acknowledgment message, the BS will retransmit the reassignment message until it receives a correct acknowledgment message from the terminal or a timer expires.
According to the above conventional reassignment method, even if the terminal has correctly received the reassignment message, if the acknowledgment message sent by the terminal is lost or damages due to environmental impact, the BS will mistakenly treat the terminal as failing to receive the reassignment message, and thus will continue to transmit the reassignment message to the terminal, which incurs irrecoverable hamper to normal communications.